As has been pointed out in copending applications, Ser. No. 434,285 and Ser. No. 434,284, filed Jan. 17, 1974, fluorinating fiber form synthetic resins to a relatively low level of from 4 .times. 10.sup.-.sup.7 to 4 .times. 10.sup.-.sup.1 mg F/cm.sup.2 creates a surface fluorinated and carboxylated product with good stain release antiredeposition properties and significant water transport properties. The improvement in water transport, or wicking properties, are believed attributable to chain scission and formation of carboxylic acid groups which occur as an incident to the fluorination reactions, with the carboxylate level increasing along with increased fluorine incorporation.
Existence of an inter-relationship between carboxylate formation and fluorination intensity limits the levels of water transport (or wicking) attainable through increasing fluorination intensity. Actually, beyond certain levels, more intensive fluorination can decrease water transport.
It has now been discovered that conduct of the fluorination in the presence of sulfur dioxide creates enhanced moisture transport.